This invention is generally concerned with a process and apparatus for monitoring a physical condition of a hose for moving abrasive materials, and more particularly with a process and apparatus for monitoring a wear condition of a portion of a hose for moving abrasive materials.
Prior art structures for guiding moving masses of abrasive materials, such as mineral bearing ores in either a fluidized or dry bulk state, generally comprise a hose including an inner liner made of an abrasion resistant material, a carcass made of a plurality of pressure resistant layers disposed in surrounding relationship with the inner liner and an outer cover made of a wear resistant layer of an elastomeric material disposed in surrounding relationship with the carcass. Moreover, the hose, which has opposite free ends, may include a reinforcing steel wire helix deployed between a selected pair of carcass layers, and opposite couplings respectively connected to the opposite ends of the hose.
Sections of these hoses are typically deployed with a bend formed therein for connection to other straight sections of similarly constructed hoses or conduits. In the course usage, the abrasive materials flowing through the hoses gradually internally erode away the inner liner, especially at the bend, followed by successively eroding away the carcass layers. If left unchecked, the abrasive materials will finally erode away the elastomeric cover without there being any significant visible sign of such internal erosion until the hose either ruptures or explodes, with consequent spillage of the abrasive materials. Accordingly, a long standing problem that users have had with such hoses has been to provide accurate early warnings of internal erosion of the inner and carcass layers of the hose, to permit timely redeployment of the hose, i.e. to rotate the hose around about 90 degrees so that the abrasive material flowing into the bend will encounter a less worn section of the hose to enable greater usage of the hose prior to replacement thereof.
Various attempts have been made in the prior art to meet the aforesaid need. For example, U.S. Pat. No. 4,446,892, issued to Maxwell, discloses the provision in a wire sensing element between plies. When the innermost layer of the hose is worn through, the sensing element is concurrently worn through or otherwise broken, thereby creating an open circuit to a continuity test. This continuity test provides an early warning of significant internal wear and the need to replace the hose before rupture or explosion. Similarly, U.S. Pat. No. 5,634,497, issued to Neto discloses the provision of a plurality of layers of wires arranged to act as a single sensing element.
More recently, the assignee of the present invention has filed PCT Patent Application Serial No. PCT/US99/07899, filed Apr. 12, 1999 which discloses an abrasive material carrying hose that includes at least two resistance wire elements that respectively have free ends. Each of the resistance elements is helically wound about a different layer of hose material, including the inner liner and one of the carcass layers of the hose. In addition, a plurality of conventional, two-pole, electrical receptacles are provided. Preferably, the free ends of one of the resistance elements are electrically connected to one of the receptacles, and the free ends of the other resistance element are electrically connected to the other of the receptacles to permit separate continuity tests of the resistance elements via the respective receptacles. Further, a different continuity testing device is plugged into each of the receptacles. The continuity testing devices each include a battery for energization thereof, a resistance monitoring circuit and a multi-vibrator driven by the monitoring circuit. Each of the continuity testing devices also includes switching structure that is manually actuatable for energizing and de-energizing the continuity testing device, and includes a test switch connected to the resistance monitoring circuit. The test switch is operable for starting and stopping continuous testing of the associated for continuity. Moreover, the continuity testing devices each include a plurality of alarm structures, including audio and visual alarms and a receptacle that is adapted to be hard wired to a remote station. The alarm structures are respectively intermittently operable by the milti-vibrator whenever the resistance monitoring circuit detects a resistance discontinuity. In practice, when the respective alarm structures of one of the continuity testing devices provides an intermittent signal, indicating that the resistance element associated with the inner liner, and thus the inner liner itself, has worn through, the user intervenes by stopping the flow of abrasive materials to the hose, followed by axially rotating the hose about 90 degrees and re-starting the flow of abrasive materials to the hose. Thereafter, when the respective alarm structures of the other continuity testing device provides an intermittent signal indicating that the resistance element associated with a carcass layer, and thus the carcass layer itself, has worn through, the user again intervenes by stopping the flow of abrasive materials to the hose, followed by replacing the hose.
In the prior art, the early warning of hose failure is thus based upon detecting a discontinuity in a resistance wire after wear-through of the inner layer or carcass layer associated therewith. Earlier warning of imminent hose failure, such as partial erosion of a given resistance element or substantial but not complete erosion of a portion of the inner liner or a carcass layer of the hose, is very desirable because it would permit earlier implementation of corrective procedures with a view to prolonging the life of the given hose. In this connection it is noted that if users had access to historical data concerning their prior hose failures, a source of predictive information would be available to permit intermediate hose rotations with consequent prolongation of the life of the given hose.
Accordingly, an aspect of the present invention is to provide an improved process and apparatus for remotely monitoring a condition of a hose. A subsidiary aspect of the invention is to provide improved apparatus for monitoring vibration of a hose. And, another subsidiary aspect of the invention is to provide structure for collecting data relating to a plurality of prior hose failures.
According to the invention there is provided apparatus for monitoring a hose that includes an inner liner and a carcass disposed coaxially of, and in surrounding relationship with, the inner liner, wherein the carcass includes at least one ply. The hose also includes an outer cover that is disposed coaxially of, and in surrounding relationship with, the carcass. Preferably, the apparatus includes an electronic hose tag. Moreover the structure for connecting the tag to the hose preferably includes a vulcanized rubber patch having an arcuately-shaped radially outwardly extending side, and having an opposite side thereof that is configured for attachment to the hose cover.
In addition, according to the invention there is provided a process for monitoring a condition of a hose that includes an inner liner and a carcass disposed coaxially of, and in surrounding relationship with, the inner liner, wherein the carcass includes at least one ply. The hose also includes an outer cover that is disposed coaxially of, and in surrounding relationship with, the carcass. The process is characterized by the steps of connecting vibration sensing structure to the hose, providing an instrumentation amplifier, providing a microprocessor and connecting the vibration sensing structure thereto via the instrumentation amplifier. In addition, the process is characterized by the step of operating the instrumentation amplifier for providing an analog vibration sample signal to the microprocessor.
Moreover, according to the invention there is provided a process for monitoring a condition of a hose that includes an inner liner and a carcass having at least one ply disposed coaxially of, and in surrounding relationship with the inner liner. The hose includes an outer cover that is disposed coaxially of, and in surrounding relationship with the carcass and an inner sensing element helically wound about the inner liner. The process for monitoring is accomplished by providing an inner sensing element, a monitoring circuit, and a microprocessor connecting the inner sensing element to the monitoring circuit. The microprocessor is operated for providing an inner sensing element continuity sample signal to the microprocessor.
Reference will be made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. The figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these preferred embodiments, it should be understood that it is not intended to limit the spirit and scope of the invention to these particular embodiments.
Certain elements in selected ones of the drawings may be illustrated not-to-scale, for illustrative clarity. The cross-sectional views, if any, presented herein may be in the form of xe2x80x9cslicesxe2x80x9d, or xe2x80x9cnear-sightedxe2x80x9d cross-sectional views, omitting certain background lines, which would otherwise be visible in a true cross-sectional view, for illustrative clarity.
Elements of the figures are typically numbered as follows. The most significant digit (hundreds) of the reference number corresponds to the figure number. Elements of FIG. 1 are typically numbered in the range of 100-199. Elements of FIG. 2 are typically numbered in the range of 200-299. Similar elements throughout the drawings may be referred to by similar reference numerals. For example, the element 199 in a figure may be similar, and possibly identical to the element 299 in an other figure. In some cases, similar (including identical) elements may be referred to with similar numbers in a single drawing. For example, each of a plurality of elements 199 may be referred to individually as 199a, 199b, 199c, etc. Such relationships, if any, between similar elements in the same or different figures will become apparent throughout the specification, including, if applicable, in the claims and abstract.